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Linux/fs/jffs2/file.c

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  1 /*
  2  * JFFS2 -- Journalling Flash File System, Version 2.
  3  *
  4  * Copyright © 2001-2007 Red Hat, Inc.
  5  * Copyright © 2004-2010 David Woodhouse <dwmw2@infradead.org>
  6  *
  7  * Created by David Woodhouse <dwmw2@infradead.org>
  8  *
  9  * For licensing information, see the file 'LICENCE' in this directory.
 10  *
 11  */
 12 
 13 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 14 
 15 #include <linux/kernel.h>
 16 #include <linux/fs.h>
 17 #include <linux/time.h>
 18 #include <linux/pagemap.h>
 19 #include <linux/highmem.h>
 20 #include <linux/crc32.h>
 21 #include <linux/jffs2.h>
 22 #include "nodelist.h"
 23 
 24 static int jffs2_write_end(struct file *filp, struct address_space *mapping,
 25                         loff_t pos, unsigned len, unsigned copied,
 26                         struct page *pg, void *fsdata);
 27 static int jffs2_write_begin(struct file *filp, struct address_space *mapping,
 28                         loff_t pos, unsigned len, unsigned flags,
 29                         struct page **pagep, void **fsdata);
 30 static int jffs2_readpage (struct file *filp, struct page *pg);
 31 
 32 int jffs2_fsync(struct file *filp, loff_t start, loff_t end, int datasync)
 33 {
 34         struct inode *inode = filp->f_mapping->host;
 35         struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
 36         int ret;
 37 
 38         ret = filemap_write_and_wait_range(inode->i_mapping, start, end);
 39         if (ret)
 40                 return ret;
 41 
 42         mutex_lock(&inode->i_mutex);
 43         /* Trigger GC to flush any pending writes for this inode */
 44         jffs2_flush_wbuf_gc(c, inode->i_ino);
 45         mutex_unlock(&inode->i_mutex);
 46 
 47         return 0;
 48 }
 49 
 50 const struct file_operations jffs2_file_operations =
 51 {
 52         .llseek =       generic_file_llseek,
 53         .open =         generic_file_open,
 54         .read =         new_sync_read,
 55         .read_iter =    generic_file_read_iter,
 56         .write =        new_sync_write,
 57         .write_iter =   generic_file_write_iter,
 58         .unlocked_ioctl=jffs2_ioctl,
 59         .mmap =         generic_file_readonly_mmap,
 60         .fsync =        jffs2_fsync,
 61         .splice_read =  generic_file_splice_read,
 62 };
 63 
 64 /* jffs2_file_inode_operations */
 65 
 66 const struct inode_operations jffs2_file_inode_operations =
 67 {
 68         .get_acl =      jffs2_get_acl,
 69         .set_acl =      jffs2_set_acl,
 70         .setattr =      jffs2_setattr,
 71         .setxattr =     jffs2_setxattr,
 72         .getxattr =     jffs2_getxattr,
 73         .listxattr =    jffs2_listxattr,
 74         .removexattr =  jffs2_removexattr
 75 };
 76 
 77 const struct address_space_operations jffs2_file_address_operations =
 78 {
 79         .readpage =     jffs2_readpage,
 80         .write_begin =  jffs2_write_begin,
 81         .write_end =    jffs2_write_end,
 82 };
 83 
 84 static int jffs2_do_readpage_nolock (struct inode *inode, struct page *pg)
 85 {
 86         struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
 87         struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
 88         unsigned char *pg_buf;
 89         int ret;
 90 
 91         jffs2_dbg(2, "%s(): ino #%lu, page at offset 0x%lx\n",
 92                   __func__, inode->i_ino, pg->index << PAGE_CACHE_SHIFT);
 93 
 94         BUG_ON(!PageLocked(pg));
 95 
 96         pg_buf = kmap(pg);
 97         /* FIXME: Can kmap fail? */
 98 
 99         ret = jffs2_read_inode_range(c, f, pg_buf, pg->index << PAGE_CACHE_SHIFT, PAGE_CACHE_SIZE);
100 
101         if (ret) {
102                 ClearPageUptodate(pg);
103                 SetPageError(pg);
104         } else {
105                 SetPageUptodate(pg);
106                 ClearPageError(pg);
107         }
108 
109         flush_dcache_page(pg);
110         kunmap(pg);
111 
112         jffs2_dbg(2, "readpage finished\n");
113         return ret;
114 }
115 
116 int jffs2_do_readpage_unlock(struct inode *inode, struct page *pg)
117 {
118         int ret = jffs2_do_readpage_nolock(inode, pg);
119         unlock_page(pg);
120         return ret;
121 }
122 
123 
124 static int jffs2_readpage (struct file *filp, struct page *pg)
125 {
126         struct jffs2_inode_info *f = JFFS2_INODE_INFO(pg->mapping->host);
127         int ret;
128 
129         mutex_lock(&f->sem);
130         ret = jffs2_do_readpage_unlock(pg->mapping->host, pg);
131         mutex_unlock(&f->sem);
132         return ret;
133 }
134 
135 static int jffs2_write_begin(struct file *filp, struct address_space *mapping,
136                         loff_t pos, unsigned len, unsigned flags,
137                         struct page **pagep, void **fsdata)
138 {
139         struct page *pg;
140         struct inode *inode = mapping->host;
141         struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
142         struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
143         struct jffs2_raw_inode ri;
144         uint32_t alloc_len = 0;
145         pgoff_t index = pos >> PAGE_CACHE_SHIFT;
146         uint32_t pageofs = index << PAGE_CACHE_SHIFT;
147         int ret = 0;
148 
149         jffs2_dbg(1, "%s()\n", __func__);
150 
151         if (pageofs > inode->i_size) {
152                 ret = jffs2_reserve_space(c, sizeof(ri), &alloc_len,
153                                           ALLOC_NORMAL, JFFS2_SUMMARY_INODE_SIZE);
154                 if (ret)
155                         return ret;
156         }
157 
158         mutex_lock(&f->sem);
159         pg = grab_cache_page_write_begin(mapping, index, flags);
160         if (!pg) {
161                 if (alloc_len)
162                         jffs2_complete_reservation(c);
163                 mutex_unlock(&f->sem);
164                 return -ENOMEM;
165         }
166         *pagep = pg;
167 
168         if (alloc_len) {
169                 /* Make new hole frag from old EOF to new page */
170                 struct jffs2_full_dnode *fn;
171 
172                 jffs2_dbg(1, "Writing new hole frag 0x%x-0x%x between current EOF and new page\n",
173                           (unsigned int)inode->i_size, pageofs);
174 
175                 memset(&ri, 0, sizeof(ri));
176 
177                 ri.magic = cpu_to_je16(JFFS2_MAGIC_BITMASK);
178                 ri.nodetype = cpu_to_je16(JFFS2_NODETYPE_INODE);
179                 ri.totlen = cpu_to_je32(sizeof(ri));
180                 ri.hdr_crc = cpu_to_je32(crc32(0, &ri, sizeof(struct jffs2_unknown_node)-4));
181 
182                 ri.ino = cpu_to_je32(f->inocache->ino);
183                 ri.version = cpu_to_je32(++f->highest_version);
184                 ri.mode = cpu_to_jemode(inode->i_mode);
185                 ri.uid = cpu_to_je16(i_uid_read(inode));
186                 ri.gid = cpu_to_je16(i_gid_read(inode));
187                 ri.isize = cpu_to_je32(max((uint32_t)inode->i_size, pageofs));
188                 ri.atime = ri.ctime = ri.mtime = cpu_to_je32(get_seconds());
189                 ri.offset = cpu_to_je32(inode->i_size);
190                 ri.dsize = cpu_to_je32(pageofs - inode->i_size);
191                 ri.csize = cpu_to_je32(0);
192                 ri.compr = JFFS2_COMPR_ZERO;
193                 ri.node_crc = cpu_to_je32(crc32(0, &ri, sizeof(ri)-8));
194                 ri.data_crc = cpu_to_je32(0);
195 
196                 fn = jffs2_write_dnode(c, f, &ri, NULL, 0, ALLOC_NORMAL);
197 
198                 if (IS_ERR(fn)) {
199                         ret = PTR_ERR(fn);
200                         jffs2_complete_reservation(c);
201                         goto out_page;
202                 }
203                 ret = jffs2_add_full_dnode_to_inode(c, f, fn);
204                 if (f->metadata) {
205                         jffs2_mark_node_obsolete(c, f->metadata->raw);
206                         jffs2_free_full_dnode(f->metadata);
207                         f->metadata = NULL;
208                 }
209                 if (ret) {
210                         jffs2_dbg(1, "Eep. add_full_dnode_to_inode() failed in write_begin, returned %d\n",
211                                   ret);
212                         jffs2_mark_node_obsolete(c, fn->raw);
213                         jffs2_free_full_dnode(fn);
214                         jffs2_complete_reservation(c);
215                         goto out_page;
216                 }
217                 jffs2_complete_reservation(c);
218                 inode->i_size = pageofs;
219         }
220 
221         /*
222          * Read in the page if it wasn't already present. Cannot optimize away
223          * the whole page write case until jffs2_write_end can handle the
224          * case of a short-copy.
225          */
226         if (!PageUptodate(pg)) {
227                 ret = jffs2_do_readpage_nolock(inode, pg);
228                 if (ret)
229                         goto out_page;
230         }
231         mutex_unlock(&f->sem);
232         jffs2_dbg(1, "end write_begin(). pg->flags %lx\n", pg->flags);
233         return ret;
234 
235 out_page:
236         unlock_page(pg);
237         page_cache_release(pg);
238         mutex_unlock(&f->sem);
239         return ret;
240 }
241 
242 static int jffs2_write_end(struct file *filp, struct address_space *mapping,
243                         loff_t pos, unsigned len, unsigned copied,
244                         struct page *pg, void *fsdata)
245 {
246         /* Actually commit the write from the page cache page we're looking at.
247          * For now, we write the full page out each time. It sucks, but it's simple
248          */
249         struct inode *inode = mapping->host;
250         struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
251         struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
252         struct jffs2_raw_inode *ri;
253         unsigned start = pos & (PAGE_CACHE_SIZE - 1);
254         unsigned end = start + copied;
255         unsigned aligned_start = start & ~3;
256         int ret = 0;
257         uint32_t writtenlen = 0;
258 
259         jffs2_dbg(1, "%s(): ino #%lu, page at 0x%lx, range %d-%d, flags %lx\n",
260                   __func__, inode->i_ino, pg->index << PAGE_CACHE_SHIFT,
261                   start, end, pg->flags);
262 
263         /* We need to avoid deadlock with page_cache_read() in
264            jffs2_garbage_collect_pass(). So the page must be
265            up to date to prevent page_cache_read() from trying
266            to re-lock it. */
267         BUG_ON(!PageUptodate(pg));
268 
269         if (end == PAGE_CACHE_SIZE) {
270                 /* When writing out the end of a page, write out the
271                    _whole_ page. This helps to reduce the number of
272                    nodes in files which have many short writes, like
273                    syslog files. */
274                 aligned_start = 0;
275         }
276 
277         ri = jffs2_alloc_raw_inode();
278 
279         if (!ri) {
280                 jffs2_dbg(1, "%s(): Allocation of raw inode failed\n",
281                           __func__);
282                 unlock_page(pg);
283                 page_cache_release(pg);
284                 return -ENOMEM;
285         }
286 
287         /* Set the fields that the generic jffs2_write_inode_range() code can't find */
288         ri->ino = cpu_to_je32(inode->i_ino);
289         ri->mode = cpu_to_jemode(inode->i_mode);
290         ri->uid = cpu_to_je16(i_uid_read(inode));
291         ri->gid = cpu_to_je16(i_gid_read(inode));
292         ri->isize = cpu_to_je32((uint32_t)inode->i_size);
293         ri->atime = ri->ctime = ri->mtime = cpu_to_je32(get_seconds());
294 
295         /* In 2.4, it was already kmapped by generic_file_write(). Doesn't
296            hurt to do it again. The alternative is ifdefs, which are ugly. */
297         kmap(pg);
298 
299         ret = jffs2_write_inode_range(c, f, ri, page_address(pg) + aligned_start,
300                                       (pg->index << PAGE_CACHE_SHIFT) + aligned_start,
301                                       end - aligned_start, &writtenlen);
302 
303         kunmap(pg);
304 
305         if (ret) {
306                 /* There was an error writing. */
307                 SetPageError(pg);
308         }
309 
310         /* Adjust writtenlen for the padding we did, so we don't confuse our caller */
311         writtenlen -= min(writtenlen, (start - aligned_start));
312 
313         if (writtenlen) {
314                 if (inode->i_size < pos + writtenlen) {
315                         inode->i_size = pos + writtenlen;
316                         inode->i_blocks = (inode->i_size + 511) >> 9;
317 
318                         inode->i_ctime = inode->i_mtime = ITIME(je32_to_cpu(ri->ctime));
319                 }
320         }
321 
322         jffs2_free_raw_inode(ri);
323 
324         if (start+writtenlen < end) {
325                 /* generic_file_write has written more to the page cache than we've
326                    actually written to the medium. Mark the page !Uptodate so that
327                    it gets reread */
328                 jffs2_dbg(1, "%s(): Not all bytes written. Marking page !uptodate\n",
329                         __func__);
330                 SetPageError(pg);
331                 ClearPageUptodate(pg);
332         }
333 
334         jffs2_dbg(1, "%s() returning %d\n",
335                   __func__, writtenlen > 0 ? writtenlen : ret);
336         unlock_page(pg);
337         page_cache_release(pg);
338         return writtenlen > 0 ? writtenlen : ret;
339 }
340 

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